fully make bs4 and soupsieve standalone in the project

lib/bs4/tests/test_html5lib.py

@@ -3,12 +3,12 @@
 import warnings
 
 try:
-    from bs4.builder import HTML5TreeBuilder
+    from ...bs4.builder import HTML5TreeBuilder
     HTML5LIB_PRESENT = True
 except ImportError as e:
     HTML5LIB_PRESENT = False
-from bs4.element import SoupStrainer
-from bs4.testing import (
+from ...bs4.element import SoupStrainer
+from ...bs4.testing import (
     HTML5TreeBuilderSmokeTest,
     SoupTest,
     skipIf,